Vehicle display screen or portion thereof with an alert icon



FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface showing our new design; and,

FIG. 2 is a second embodiment of a front view of a display screen or portion thereof with a graphical user interface showing our new design.

The broken lines shown in FIGS. 1-2 of a display screen or portion thereof form no part of the claimed design. 

CLAIM The ornamental design for a vehicle display screen or portion thereof with an alert icon, as shown and described. 